Fertile Period Calculator
Compute fertile window and ovulation day from the first day of the last cycle and the average cycle length.
- Predicted ovulation
- Fertile window
How does it work?
Ovulation occurs about 14 days before the next cycle. The fertile window is estimated as 5 days before to 1 day after ovulation (sperm survive ~5 days, egg ~24h).
The method is statistical and works best for regular cycles. For better accuracy use ovulation tests or basal body temperature.
Not a contraceptive method nor medical advice.
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